<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>双飞翼布局</title>
</head>
<body>
  <header>头部</header>
  <!-- 如果不添加 div 那么会产生浮动塌陷 -->
  <div class="clear-fix">
    <div class="wrapper">
      <div class="content">
        主区域
      </div>
    </div>
    <div class="left">
      左区域
    </div>
    <div class="right">
      右区域
    </div>
  </div>
  <footer>尾部</footer>
</body>
<style>

  header {
    background-color: brown;
    height: 100px;
  }
  
  .wrapper {
    width: 100%;
    background-color: burlywood;
  }
  .content {
    margin: 0 100px;
  }
  .left {
    background-color: cadetblue;
    margin-left: -100%;
  }
  .right {
    background-color: chartreuse;
    margin-left: -100px;
  }
  footer {
    background-color: chocolate;
    height: 100px;
  }

  .left, .right {
    width: 100px;
  }

  .wrapper, .content, .left, .right {
    height: 100px;
    float: left;    
  }

  header, footer, .wrapper, .content, .left, .right {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 30px;
  }

  .clear-fix::after {
    content: "";
    display: block;
    clear: both;
  }
</style>
</html>